CM modeling method and EMI reduction method of transformer are important for isolated converters to meet EMI requirement. In this survey, the CM modeling methods for the transformer are systematically summarized first based on effective frequency range from low-frequency to high-frequency. Their advantages and disadvantages are also detailed compared. Furthermore, the CM EMI reduction methods for transformer are reviewed and compared. Finally, two potential research issues are defined, and preliminary research approaches are given with the analysis of the previous reviews.
